This study will develop statistical methods for estimating the standardized risk difference and the common odds ratio for a number of contingency tables. The optimality properties of the developed methodology will be investigated and established. The likelihood equations are to be derived and the weighted least squares, the weighted total, the maximum likelihood and the conditional maximum likelihood and the conditional maximum likelihood methodologies are to be examined. The study has been extended to do comparison of a number of contingency tables in the form of hypothesis testing. All these methodologies have wide applications to epidemiological studies, biomedical studies, genetics and other disciplines. Continuation of development of statistical methodology is planned. Tests of hypothesis about the two sequences of probabilities are to be developed. Statistical properties are to be investigated. Applications to substantive fields such as genetics will be examined. This work is still in progress.